Fan and blower unit having the same

摘要

A cooling fan includes a cylindrical boss portion, a plurality of blades extending from the boss portion in a radial direction and a ring member integrated with radial outside edges of the blades. The ring member has an axial dimension smaller than an axial dimension of the blade at the radial outside edge, with respect to an axial direction of the boss portion. The ring member has an extending portion extending in a form of bell toward an upstream position of the blades with respect to an air flow. The extending portion is disposed such that a base point connecting to a body portion of the ring member is arranged in a range that begins at a point 25% and ends at a point 85% of a distance from an upstream end of the radial outside edge of the blade with respect to the axial dimension of the blade.